Chromatic harmonicas comprise a body having provided therein a series of adjacent cavities, each containing a plurality of reeds which are adapted to produce a musical note of a predetermined pitch upon passage of air thereover. Each cavity has a pair of corresponding reeds including a blow-reed, which produces a blow-note responsive to the blowing of air into the cavity, and a draw-reed, which produces a draw-note responsive to the drawing of air from the cavity. The harmonica further includes a slide key which, when activated, raises the pitch of the note formed by each reed, by a half tone (to the sharp).
The cavities of the harmonica are arranged in cavity sets, each of which represents an identical scale in one of a plurality of octaves. The blow-note of the final cavity of each cavity set forms the blow-note of the first cavity of that cavity set, raised one octave. Each cavity set is adjacent to a cavity set corresponding to at least one of a higher and lower octave, the cavity sets being arranged sequentially and progressing from lower to higher octaves from left to right with respect to the playing position. In harmonicas of this type the scale note of the harmonica is always formed by a blow reed. However, as the scale contains only seven whole notes, assuming the lower scale note is a draw-note, the upper scale note for each cavity set would normally be a draw-note. To prevent this, the position of the two reeds of the final cavity of the cavity set are reversed. More concretely, in a C-scale cavity set, the blow-notes should be, in sequence, C, E, G, B and the draw-notes should be D, F, A, C, and to prevent the high C from being a draw-note the position of the reeds for the B and high C are reversed. As a by-product of this reversal, however, the blow-note of the final cavity of the cavity set is a repeating note, identical to the blow-note formed by the first cavity of the adjacent, higher octave set.
During play, one often loses track of which of the two adjacent cavities is to be played. Such is not critical when a blow-note is desired, as the same blow-note is formed by the blow-reeds of each of the adjacent cavities. However, when one is required to play a specific draw-note related to the duplicated blow-note, it is imperative that one be aware of which cavity is to be activated, as the draw-notes of the adjacent cavities are not identical. While this problem may not affect the skilled artisan, it may prevent the novice from quickly learning the instrument. Thus, it would be advantageous, to provide a means for allowing the less experienced player to differentiate between these adjacent cavities, therefore providing for an accelerated mastering of the instrument.